Recruiting the immune system to fight against tumors should be an effective, general approach to combating cancer, but designing a vaccine that can achieve the necessary level of immune response has been difficult. One approach to bolstering immune response to cancer has been to magnify the interaction between antigen- presenting tumor cells (tumor APCs) on cytotoxic T cells. Microspheres that present tumor-antigen-loaded major histocompatibility complexes (pMHCs) on their surfaces achieve this goal to some degree by mimicking the behavior of tumor APCs. We hypothesize, however, that the impact of these microsphere immunogens would be greater if they mimicked the structure of the immunological synapse that naturally forms between APCs and T cells. We propose to fabricate Au-ringed silicon dioxide disks that will allow us to spatially arrange different APC receptors in the way they would be in a mature immunological synapse. The interaction of these nanostructured, artificial antigen-presenting constructs (naAPCs) with antigen-specific T cells from knockout mice will be characterized in vitro and in vivo. In particular, we will analyze how strongly naAPCs bind to these T cells and whether the naAPCs activate the T cells against tumor antigen. We expect that these experiments will lead to a larger effort that evaluates how well naAPCs stimulate expansion of tumor- specific T cell populations in vivo, and how effective these agents are at helping inoculated mice fight against melanomas. Our expectation is that the successful demonstration of naAPCs could be immediately translated to in vitro tests and clinical trials on human T cells, as has been the case for microsphere aAPCs. Towards this goal, we propose to: 1. Fabricate micro-/nano-structured scaffold disks for naAPCs;2. Attach immunological synapse components to naAPCs;3. Assay binding specificity of functionalized naAPCs to T cells, and compare avidity to that of microsphere- based aAPCs;and 4. Assay T-cell activation and differentiation in vitro, and compare to aAPCs.